textproduct: Albany

WHAT HAS CHANGED

Continued to increase PoPs and QPF Friday night as a weak disturbance tracks across the area. This will lower the threat for frost Friday night. Continued mention of slight chance to chance PoPs for southeastern areas Saturday evening/night as a coastal low tracks well to our south and east. Also increased wind gusts and lowered dew points/RH Sunday behind the departing coastal low.

KEY MESSAGES

1) Below normal temperatures with isolated to scattered showers at times expected through the weekend. Frost Advisories may be needed Saturday night for portions of the Hudson Valley, southern Taconics and Litchfield Hills where the growing season begins May 1.

3) Unsettled pattern expected to develop next week, with multiple opportunities for rainfall Tuesday through Thursday.

DISCUSSION

KEY MESSAGE 1... As of 2:40 PM EDT...1004 mb sfc low is tracking off to our north. Showers that were around earlier this morning associated with this cyclone are departing into central New England, with some partial clearing and generally dry conditions across our region at this time. The system's cold front is now located off to our east in New England as well, with winds having switched to the W/NW for most areas. Highs this afternoon will be mainly in the 40s (terrain) to upper 50s (valleys. Breaks of clearing continue to develop overnight tonight, especially for valley areas. Temperatures will be on the cool side with lows mainly in the 30s, but it is not expected to be cold enough for frost in areas where the growing season officially begins May 1 (Hudson Valley and Litchfield County).

Our weather tomorrow will continue to be dominated by a large upper- level low (ULL) centered north of the Great Lakes, with the upper flow blocked by ridging near Greenland. With the associated cold pool aloft nearby, morning clearing will lead to more afternoon clouds as we easily hit the convective temperature with daytime heating. A few isolated showers are possible as well, mainly for western areas. Tomorrow night, a weak impulse aloft becomes negatively tilted as it rotates around the periphery of the ULL. With an associated inverted sfc trough, there should be enough forcing to allow for at least scattered showers Friday night. We bumped up PoPs to high-end chance and added a few hundredths to around a tenth of an inch of QPF for much of the region Friday night into very early Saturday. Given more clouds and showers, frost now does not look to be much of a concern Friday night.

Saturday, will be very similar to Friday with more PM clouds and a few isolated showers as we continue to feel the influence of the ULL. A southern stream disturbance will be phasing with the ULL Saturday/Saturday night, leading to a developing sfc low tracking to the southeast of our region. 12z guidance continues to show a track southeast of the 40/70 benchmark, so while most areas should miss out on the rain, some showers can't be ruled out across the Mid Hudson Valley and Litchfield County. Saturday night looks to feature the best chance for some frost, but with this system trending closer to the coast over the last day or so in the model guidance there are now questions about whether or not more mid and high cloud cover will keep temperatures warm enough again. If frost occurs, best chance would be the upper Hudson Valley where relatively less cloud cover is expected.

The coastal low pulls away to our east Sunday, with an area of high pressure sliding across the southeastern CONUS. We will see low- level cold advection and deep mixing Sunday with a tightening pressure gradient between the departing low and the aforementioned high, so have bumped up winds and lowered dew points and RH from the NBM. As the sfc low tracks off to our northeast Sunday/Sunday night, flow aloft becomes more zonal and low-level flow. While WPC has largely stuck with the NBM's slight chance to chance PoPs Monday everywhere but the Mid Hudson Valley, some 06z and most of the 12z guidance has backed off on precip chances Monday which is the solution we are leaning towards. Given that it will be breezy and deep mixing may help offset any moisture advection, we will therefore mention that Monday could be another day with fire weather concerns. That said, there remains some forecast uncertainty given the 4 day lead time.

KEY MESSAGE 2... Large-scale flow remains blocked with persistent upper troughing to our west through the middle of next week. A warm front looks to lift north across our region Monday night or Tuesday, as sfc low pressure tracks well to our northwest. Uncertainty remains in the timing of the cold frontal passage, but guidance is in fairly good agreement for this lead time that the cold front and associated showers should reach our region Tuesday or Wednesday. The front may also stall nearby, with deterministic and ensemble guidance suggesting the potential for a wave of low pressure developing along the front to bring additional rounds of showers to the region through the Wednesday/Thursday timeframe. Temperatures should trend back to near or even slightly above normal Tuesday until the cold front arrives. However, these warmer temperatures will be short-lived, as the CPC is expecting below normal temperatures and above normal precip for days 8-14.

AVIATION /00Z FRIDAY THROUGH TUESDAY/

Through 00Z Sat...VFR conditions are expected the next 24 hours for KGFL/KALB/KPOU/KPSF with a broad upper low near the region. Sct-bkn stratocumulus and mid level clouds will persist tonight in the wake of the cold front. Some decrease of the low-level clouds will occur in the mid to late morning prior to 16Z/FRI with lingering mid and high clouds ahead of the next disturbance approaching from the south and west. Clouds will continue to thicken and lower towards the end of the TAF cycle when some showers will arrive Fri night.

The winds will be west to northwest at 5-12 KT early tonight with some gusts around 20 KT at KALB/KPSF. The winds will decrease from the west to northwest at less than 10 KT and may become light to calm near KPOU overnight. West/northwest winds will persist in the late morning through the afternoon at 5-10 KT.

Outlook...

Friday Night: Moderate Operational Impact. Chance of SHRA. Saturday: Low Operational Impact. Slight Chance of SHRA. Saturday Night: No Operational Impact. NO SIG WX. Sunday: Low Operational Impact. Breezy. NO SIG WX. Sunday Night: No Operational Impact. NO SIG WX. Monday: Moderate Operational Impact. Breezy. Chance of SHRA. Monday Night: Moderate Operational Impact. Breezy. Chance of SHRA. Tuesday: Moderate Operational Impact. Breezy. Chance of SHRA.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.